Electron discharge power amplifier



June 27, 1950 P. T. SMITH ELECTRON DISCHARGE POWER AMPLIFIER 7Sheets-Sheet l Filed June 29, 1948 l .INVENTOR BY www gaag ATTORNEY June27, 1950 P, T SMH-H 2,512,859

ELECTRON DISCHARGE POWER AMPLIFIER Filed June 29, 1948 '7 Sheets-Sheet 2I 'HH ll EIL- w. e /57 I l VENT 2211'12517 faz/L ATTORNEY June 27, 1950P. T. sMn-H ELECTRON DISCHARGE POWER AMPLIFIER 7 Sheets-Shea?I 3 FiledJune 29, 1948 www e. gaa@ June 27, 1950 P. T. SMITH ELECTRON DISCHARGEPOWER AMPLIFIER '7 Sheets-Sheet 4 Filed June 29, 1948 1 w' Y- 4.2M

June 27, V1950 P. T. SMITH 2,512,859

ELECTRON DISCHARGE POWER AMPLIFIER Filed. June 29, 1948 '7 Shee'ts-Sheet5 INVENTOR I l lATTO EY June 27, 1950 P. T. SMITH ELECTRON DISCHARGEPOWER AMPLIFIER '7 Sheets-Sheet 6 ill (fi,

Filed June 29, 1948 ma@ aw June 27, 1950 P. T. SMITH ELEcTRoN DISCHARGEPOWER AMPLIFIER '7 Sheets-Sheet 7 Filed June 29 1948 aplasta Anadditional object of my invention is to provide a push-pull device whichAis suitable for amplifying high power of high frequency beingespecially useful in balanced push-pull ampliers or modulators wherefreedom from self-oscillation is essential.

The electron discharge device of my invention is to be used as amodulated amplifier and a further object of my invention is to providesuch a device for grid modulation wherein very high cathode emissiondensities are obtained and high percentage grid modulation may becarried out without causing noticeable amounts of grid current to flowon-the positive cycle of the modulation currents. This improves theoperating characteristics and reduces the electrode cooling problem.

Manufacture of an electron discharge device .with compact closelyrelated electrode structure is diflicultand an additional object of myinvention is to provide a device having precision parts which canbeaccurately constructed andeasily assembled and lined up and in whichalignment and spacing are rigidly maintained during operation thusminimizing change of electrical characteristics.

In describing my invention in detail, reference will be made to theattached drawings wherein .Figure l illustrates symbolically the tubeelements and connections of an electron discharge device arranged inaccordance with my invention and included in a basic repeater circuit;Figures 2, 2a and 3 illustrate symbolically the electron emittingelectrodes, electron control electrodes, screen grid electrode and anodeand also illustrate the beam forming electrodesv and the 5 manner inwhich they concentrate the emitted electrons and guide them toward theanode and .prevent them from reaching the control grid or screen grid inmaterial amounts to be absorbed. z thereby; Figure 4 is a viewtransverse to the 5 longitudinal axis of my electron discharge devicepartly in section to expose the general electrode structure and detailsof the anode electrodes and `mounting and electrode cooling systems;Figure `5 is a view similar to that of Figure 4 but taken 55 about atright angles thereto; Figure 6 is a plan .view of the end of my electrondischarge device showing the main header and the uid cooling conductorsand .electrical conductors passingtherethrough; Figure 7 is a sectionalView trans- 50 verse to the electron discharge device axis of vFigure 5;Figure. 8 isa perspective view of the cathode elements, beam focusingelements and control grid elements and supportsfor the same;

Figure 8a illustrates details of the cathode sup- 65 port as Viewed fromthe opposite side; Figure 9 is an enlarged elevation taken along thelines .9 9 of Figure 7. It shows details of the cathode mounting blocks,cooling circuits and electrical circuits therefore andthe control gridsand their mounts and cooling fluid and electrical circuits; Figure l0 isan exploded perspective view of the screen grids and the manner ofmounting the same. This figure also shows details of a heat shield forthe cathode and supporting means for 'the control grid; Figure 11 is aperspective View showing the manner of mounting the neutralizingcapacitors built into my improved electron discharge device structurefor cross coupling the anodes and control grids; Figure 12 is anenlarged view of the relationship of the electrodes of my device. Thisview is taken along the lines |'2-l2 of Figure 7; Figure 13 is asectiontaken along the line l3-I3 of Figure 5. This gure shows details of thecathode support structure; and Figure 14 shows in detail a supportmember between the cathode support structure and the control gridsupport to prevent movement of the control grid transverse to thelongitudinal axis of 15 my novel device.

Briefly, an electron discharge device made in accordance with myinvention includes an evacuated envelope containing an electrodeassembly comprising a two section cathode, two first or control grids,two second or screen grids, two anodes, beam focussing elements arrangedadjacent the cathode elements of each cathode section with screen gridto screen grid, screen grid to cathode, and cathode section to cathodesection coupling capacitors and neutralizing elements all combined anddisposed within said envelope to form an internally neutralized deviceof the screen grid type with low impedance between the cathode sectionsand between the screen grids.

In Figure 1, I have shown by simplified basic wiring diagram usingelectrode and circuit element symbols, my novel tube in a push-pullrepeater or amplifying circuit with an input transformer T and an outputtransformer T. Reference will be made to this figure in the descriptionwhich follows to explain the novel features of my invention. In Figure1, the reference numerals or characters applied to the electrodescorrespond to those used in the detailed description which follows in sofar as possible. In this figure, it will be noted that couplingcapacitors Csg are shown between both screen grids and the cathodestructure. Coupling capacitors CK are also supplied between the cathodesections and neutralizing capacitors NC are supplied between the platesand control grids. The capacitors CK and Csg in series are between thetwo screen grids. All capacitors are built into the tube structure.Furthermore, the screen grids are directly connected together by lead 1so that they are at the same In order to provide an electron beam havinghigh current densities and to permit the close spacing of the controland screen grids which is necessary for eiiicient high power operation,the electric eld and 4electron configuration becomes important. In thepractice of my invention, the electron field configuration .at and nearthe cathode is as illustrated in Figures 2 and 2a of the drawings. Theelectric eld'is such as to form the electrons, leaving thev cathode,into concentrated beams which are directed toward the anode. Theelectric field configuration is obtained by use of beam forming elementsadjacent the cathodes operating at the cathode potential or if desired apotential negative with re- 30 are thefocussing elements. In the tubestructure there are a large number of cathode elements 2i) in groupsthere being three ormoreigroupsia's desired."Thecathodelelements.ofFigure 2;haye at emitting surfaces, those .ofFigurelZacare curved `slightly vas shown. The .dash 'lines .indie catevthe electron :pa-tbs. The electricleldqnearthe electron emitting surfaceis .such .that .the electrons :leaving .this surface `are .subject .to.a force which Ihas acomponent directed .towarda plane through thecenter oftheemittingsurface and perpendicular toit, this force.component being .greatest in the region .of .the edges of theelectronemittingelement. I prefer .to utilize *.an arrangement .as shown:in Figure `3. .In .thisarrangement, shownschematically, the .cathodeele-l ments 2l) comprise .at emitting .surfaces inter. posed :between.the focussing elements.. 3B .of `similar shape .parallel withandspaced.from .thecathodes. i'lhesurfaceslof. the focussing elementsextendvbeyond thesurfaces of .the emitting cathodes. 'Bhe first grids or:control electrodes .'22 .are in line withA the focussing elements as.are .the screen grid electrodes 25. The anode structure., not shown inthis figureis `disposed beyond the screen .grids .and the Aelectronsfrom theemitting surface follow .parallel paths .between .the controland screenelectrodesto reach the anodes. .Similar 'but .opposedelectrode and .beam guiding elements are alsoused `in/rny push-.fpull.electrondischarge device. vAn .embodiment Lof my .device .is.illustrated in the `remaining guresof thedrawings. .Thiedevicecomprises an .electron discharge vdevice clo sure .member .includingasshownin Figures 4, 5 and 6., headers :lll and .lll separated.lyacylin-Adrical `portion l2 as will be .developed later. The envelope.enclosesadouble cathode K, as shown in Figures '1, .8 and `8a.,emitting electrons in opposite directions, electron beamfocussingelements 3c associated with the cathodes,.control grid elements22 and 2:2 facing the cathodes and v.beam focussing elements, screen.grid elements 2.5 and facing the control v.grid elements and anodes26andf2' facing the screen grid elements.

The cathode K comprises three sections as shown in. Figures 1, .8. 8aand 9 each of which sections .areas shown in detail in Figures 8 and 8awith U-shaped cathode elements 2c ,spaced as. shown. The control grid.structure Cg and Cg, Figures 7, .8 .and 9 comprises control gridelements 22and22' mounted close to the respective cathode sections. Thenovel screen grid structure Sg and Sg, vFigures 7 and 10, .comprisingelements v25 and `25 are mounted close to the control grids. The anodes2K5 yand '25', Figures 4 and '7, are mounted facing the screen gridstructures. Beam yfocussing elements 3c and 33' are carried by thecathodesupport being mounted` between the cathode elements 2i) which areU- shaped. The relationship of the elements is shown in Figure 12 whichis an enlarged View on the vlines |2-i2of Figure '7. The ends of all ofthe U-.shaped cathodes are .spot Welded to a strip 32 cna main support35, Figures 7, 8, 8a and 9. The ends 4of the remaining legs orgroups(here 3 groups) of the U -shaped cathodes are spot welded to threestrips 3.3, 33' and 33"., Figure 8a, on secondary cathode blocks 34, 34and 323. Note that in the sake of clearness, Views of opposite sides ofthe-cathode supports are shown in Figures 8 and 8a. The main support 35is bolted to a lug Lon the header I0 as shown in Figures 4 and 5. Theelectron focussing elements 3i) and 33 and screen :grid structure are.also carried by this-main support. This `main support'is also used toprevent transverse movement ofthe grid electro delstructure as-descrbedhereinatern The control' gridsareseparate and:theiristructuresare each-.supported by its cooling :fluid :pipes .CPand CP as shown in Figures 5, 6 and '7. rllhese pipes are sealed intoglass inserts in :the header Ml. Thus all of 4the lelectrodes, except.the-.anodea are. supported .by thermain header .L0 andall-.o-f. theelectrodes supported bythe main iheader .ml are provided'. with .coolingfluid i conductorswhich are sealed .intheheader .t0 and, '.withtheexceptioneof one.coolingconductorior thecathodestructures, are:insulated-theretrom so .that :the cooling .fluid conductors also serve,as electrical connectors.

y The-anode .electrodes 26 .and .25' .are .mounted on.their-.cocling.fluid l-pipes Whicharefsealed into the header vleasshownin Figures Sand-6. `'The headerl l .is adjustable .as is .theheader .110-50 that 'theancde .electrodes .may .be moved .relative tothe .other electrodes. to establish mechanical andelectrical symmetrybetween -theanodesand screen grids.' v

The cathodefstructnrepand .beamiocussingielements, -control :grids Aand.screen .grids .andthe supports. or .the .saone willnow gbedescrbed. indetail. The .cathode is lin :three sections .and the. sections .beingzsimilar, Aone .only .will be described fully. Anexplcded .Viewoftheicathode andbeam focussing- .elements and .support A.and .controlvgrid arelshown vin Figure .8. .'Ihese. .elements .are mountedwithinothe screen jgrid .elementsshown in :detail .in .Figure .10..

The .cathode comprises, .as illustrated in .Eig-

ures 1.8, 8a and :9, Aapluralityof aU fshaped wire .or strap-.likerelements .2D lwhichmaybe of tantalum or .thesame coatedwith thoria`.ora .matrix of tungsten-thoria. -Onefleg-.o each Aof theelements portmembers 311, .3.4 :and .34 and .the Astrip .32, lis

bolted. to, the vliquid .cooled main .support .member-.35. Thethreemembers 3.4.3.4' .an.d.-3.4f. :are shown dotted in Figures aand, 5,and in .detail in Figures 7, 8 and 8a. The main Isupport mem-` ber.3,55 andsupport members 35, 3.4. and .34.` are separated and insulatedfrom .each `other` .by .a strip of mica. Thus members 34, .34' and 3.47are insulated Vfrom each, other andmember 35` exceptgfertheconnectionsormed therebetween by the U-Sheped cathodes.` .The`capacitors formed between .members 34., 34C. 34" and Slllermit the.cathode I.sections to operate at the same A. C. potentialfsince theimpedance between -the cathode sections has been reduced substantiallyto zero. The ,impedance between the individual cathode elements andbetween the sameand the focussing elements and between focussingelements isextremely low `because of` thenovel mounting used. The doublestructurer operates as onestructure with respect to alternating currents`of .high `frequency. The vadvantage of .such an ,arrangement inamplifiers is apparent.

The members .34, 3d .and 3.4 and-.3.5 are bolted together by bolts 36.This structure is vshown'in detail in `section in Figure 13 taken on thelines I3.-l'3 of Figure 9. In the embodiment described there are threecathode assemblies each compris-v ing a group of .cathode elementssupport'as described. There may :be more groups oriewer groups ofcathode elements depending .on the number of phases of filament currentto `be used. Straps '33, 33 .and '33 are boltedto secondary cathodesupport members 34,34 and 34.. There isa memberi34f34 and.34;fcrreachcathode secsA tion and these members 34, 34' and 34" are as describedabove bolted to the member 35 which is the main cathode and beamconcentrating element support.

The members 32 and 33, 33 and 33" also carry integral therewith or spotwelded thereto the beam forming and focussing electrodes 30 and 30 ofVappropriate metal such as tantalum. These electrodes are run at thecathode potential and neither emit nor collect electrons. The focussingelectrodes 30 and 30' are integral with the cathode blocks and aretherefore cooled by the cathode support cooling fluid. They merely serveto direct the electrons and guide them toward the anode and away fromthe grid and screen grid as shown in Figures 2 and 3.

The main cathode support 35 extends beyond the members 34, 34 and 34 asis shown clearly in Figures 4 and 5 and is fastened by bolts 38 to themain header support I0. The main support flange-like header IU alsoseals the end of the electron discharge device. The envelope includesthe metallic cylindrical member l2 with a flange 44 on the outerperiphery thereof which is drilled and threaded for bolts 46 whichcooperate with the ring 48 shouldered at 4l to bolt the main header llland member I2 together. To make a vacuumtight joint, a copper ring 50 isput between the bearing surfaces of the main heater I and cylindricalmember I2. A cylindrical member 49 is used as a spacer between the outerperipheries of ring member 44 and member 48. The other end of theelectron discharge device is closed in a somewhat similar manner. A ring44 is welded or otherwise fastened to the outer periphery of member |2and the ring member 44 is threaded to receive bolts 46' passed through aring member 48 shouldered at 4l' to engage the other main header I0'. Tomake a vacuumtight joint a copper ring 50 is inserted between themembers I0' and |2. It will be noted that a very rugged tube structurehas been provided and further that, as will be developed as thedescription progresses, the tube structure is easily built up andassembled.

Returning now to the cathode structure, it will be seen by reference toFigures 8a, 9 and 13 the cathode is in three sections and three phasesof heating current are supplied thereto. The three cathode supportblocks 34, 34' and 34" each have nuid channels FC therein through whichthe cooling fluid may be circulated. The channels partly shown in saidfigure may be formed by drilling or otherwise and are connected by uidconductors 60, 60 and 60" (Figures 5 and 6), each including inlet andoutlet pipes, to a source of cooling fluid not shown. The iiuidconductors pass through three seals 62, 62 and 62", Figures 4, 5 and 6,in the main base plate l0. In order to expose the member 35, lug Landbolts 38 and the metallic shield between the control grid and anodeleads, described hereinafter, the fluid conductors 60, 60' and 60" areshown in part only in Figure 4. The fluid conductors 6U, 60' and 60 alsoserve as electrical conductors of heating currents for the cathodemember 2|) and are insulated each from the other and from the member 35.The three seals 62, 62' and 62" are similar and details of seal 62 areshown in Figure 4. A steel cup 64 is welded into a circular opening inthe header l0 and a Kovar cylinder 66 is welded to the cup 64 and/orheader lll. A glass bead 68 is bonded to the Kovar member 66 and a Kovarend pipe l0 is bonded to the glass bead 68. The fluid conductors 60" arethen passed through a metal plug 1| (Figure 6) which is welded into theend member 10. The mica sheet 31 insulates the filament support blocks34, 34 and 34" from the single filament support blocks 35. The bolts 36pass through ceramic or glass rings 36', Figures 9 and 13, and washers36" of ceramic or the like material to prevent conductive couplingbetween members 34, 34', 34" and 35 by way of bolts 36.

The main cathode support member S5 is also cooled by :duid in conductors'l2 one of which is the fluid inlet, the other the fluid outlet. Thesefluid conductors shown in Figures 5, 6, '1, 9 and l0 are sealed in andconductively connected at 14, Figure 5, to the main base plate l) andserve as the common cathode ground connection. In the embodimentillustrated, three phase heating currents are used and phases No. 1, No.2 and No. 3 may be supplied from a source not shown, to leads 60, 60 and60", respectively. The use of three phase heating current reduces powersupply hum.

It will be noted that the main support 35 is conductively connected tothe main shell |2 of the tube, etc. and is at ground R. F. and D. C.heating current potential as illustrated in Figure l. The members 34, 34and 34 and 33, 33 and 33 and the ends of the cathode members 20 weldedthereto are coupled to the member 35 and ground by the very largeparallel by-pass capacitors formed between members 34, 34' and 34",respectively, and the main support member 35. The capacitors found bythese elements are shown by dotted lines in Figure l. Thus the entirecathode structure is at ground radio frequency potential. This reductionof impedance between the cathode sections adds materially to thestability of operation of the tube structure in high frequency push-pullamplifying circuits.

The structure described above and hereinafter provides electroniccircuit and mechanical advantages that are of particular significancewhen these structures are incorporated in amplifier tubes. I haveprovided liquid cooling of the mounting, supporting and lead instructures thereby reducing the thermal expansion enough to maintain theelectrode alignment in normal operation substantially as establishedduring assembly. The accurate alignment that can be obtained duringassembly and retained during normal operation along with mechanicalsymmetry makes possible a grid to cathode and grid to screen gridcapacitance balance between the two tetrode sections.

The control grid elements 22 and 22 are fastened to or made integralWith their respective supports 2| and 2|' as shown in Figure 8. Thesegrids are rod-like elements of like length which t tig-htly into holesof like depths drilled into the edges of supports 2| and 2|. It is to beremembered that with respect to electron emission from the cathode, thecontrol electrode elements 22 and 22 are in line with the beam formingand guiding elements 30 and 36 to outline passageways for the electronsto pass from the cathode elements in concentrated sheets to the anodes.The grid members may be molybdenum and may be silver soldered orotherwise fastened to the edge of the supports 2| and 2|'. The controlgrid base members 2| and 2 are supported by the concentric cooling fluidconductors CP and CP to which they are fastened by soldering orotherwise as shown in Figures 7, 8 and 9. The fluid conductors CP andCP' in addition to acting as the inlet and outlet for the cooling fluidalso serve as electrical connections to the controlfgrid electrodesI and.supports fory thesegrids electrodes. The grid support and cooling iiuidconductors Cl? and CP are sealed'into the header Il) `as Shown infFigures and 6. This seal is quite like the seal 624- described aboveand willbe described briey. A cylindrical-.like Kovar mem-ber i8 iswelded to or otherwisefastened by. a vacuurntight joint to the headerI0. A glass member 8.0 is sealed to cylinder 18 anda K ovar member 8,2is bonded to.- the glass member 80,. The pipes CP and CP pass through avacuumtight plug like member in the end of member 89,. Itmay be notedhere that the grid electrodes are supported rigidly byv the members CP,C?" andmaintained in fixed closely spaced relation. to. the cathodes. Inoperation there may be. some longitudinal movement ofthe gridsand suchis permitted.v However, there is to be no ltransverse twisting orswaying of the gridsl andadditional means to fix the grids in thisrespect. will bedescribed later.

The, grid structure disclosed provides a sturdy mechanical support withIaccurate alignment and spacingv of theeleinents is maintained duringthenOrmaLoDeratiQn of the device in which the grid is, mounted, This.,isobtained by the effective cooling oi the grid supporting pipes Iprovide andv cooling ofthe. attached glassseals which eliminates.misalignment. of. the electrodes bv thermal expansion dueto energyabsorbed at the control elements or power dissipated in the lead in, andsupport. pipes. The. effective cooling of the. sunnortingpipes.providesa means of cooling the grid elements and thus prevents excessiveelectron emission from thesel elements. The element. length is. chosenrelative to the. element cross section so as to permit practically allofthe. power dissipated in the elements to be conducted to a coolantcirculated in the supporting pipe.`

The duplex screen electrodes. and z5' are mounted with good` thermal andelectricalV contacts in rigid frame. members. shown. in. detail. inFigures. 'l and 1.0.r These frame membersv comprise rigid. strong sidepieces 21,21 and 2 9. and 29' fastenedtogetherlou end piec.es.85.,.85'(at header mend). and 3.7. and 31' at the. other end. The two framelikemembers.. are held in parallel relation by. strong end memberseaand 89',which run the iull4 length. of. the screengrids and hold. the screengrid structures.y in, parallel planes and. prevent relative movement.thereof in any, direction-` The side. nieces4 21.', 2J and 1.9, ze: areshown. in Figules '7, leand- 113.. The support 2 1, 21 and 29, 2.8. withend. pieces. 8.3,. 89 is made as strong as reasonably possible to keepthe electrode spacing xed. The. screen grid supports 2l and 2l', arebolted. to the. main support member Baby bolts all.. (Fgurel) passing,through ceramic o r the like sleeves... 9c which insulates the. boltsfrom the members 314', 34", 34" and 35.'. The members 2.7" and are.insulated from the members 34, 3d', 34" anden. by mica. sheets. St. andS5...

The screen. grid supports 2l and 2l' and 29 and 28' have fastenedthereto cooling fluid conductors, 9G and` ill which extract heat fromthescreen grid supports. These fluid conductors take nart, iny supportingthe screengrid structure and this support taken. with theframemembersand supports described above include the screen grids instr-ong closed rectangular frame. members with transverse spacer piecesS9 and 89, running the `full. length of the framemembers to keepr theexact spacing between the screen grid electrodes. The grid-like rods25.- and 25.' are two. sections and are silver soldered in holes intheinner edges 10 ofsupoorts 2.1, 2.1.! and. 29-and.. 2.9!. The. screengrid rods 2.5 and25.' extend from the said inner edges of the sides.ofthe. frame toward each. other but do notmeet. This. structure. is usedto intere rupt circuits at which undesired oscillations V ture.y Thecanacitors thus formed are snpwnaby.

dotted lines in Rigore. 1.-. 'Ilius the screen.. grids operate. atsubstantially ground.. 1.1;. without usine. external br-nass.capacitors. and the. stability ofv the device in high. frequencycircuits is. en.- hanced.

The. screen. eridsare. cooled by lluid circulated in conductors. 9,5andSl' which assliown uros 5. and. 6., .iced into common conductors .8.8and SBI as shown .inlieures 5 and 6.. These conductors 9.8- and 98' aresealed into a plus a metal. ring 9.9. such as Kovar which in.turnissealed. intoa elassmember lutin turnsealed into amstel, such as.Kovanring. |112. welded or otherwise iastened into the mainiheader l0.'seal. issiinilar to the. seal 6.2" described above.` These fluid con.-ductorsalso serve asconductors for theel-G. and Di-C.. connections...between the. circuits. and.v the screen grid electrodes,4 and. are.. in.lated from the main header lbvthe alassio rt., Thus the screen grid,control grid and cat-.. dc and beam forming electro-des.. are. allrigidly with. respect to each other and even.. though. the dis:tancesbetween these. electrodes are. small, short circuits therebetween.cannot take piace..

Becauseof. the novel. construction of the. screen grids and thearrangement and cooling.v thereof, It have iorovidedcircuit,y thermaland mechanical advantages not. known licretof..oreV Several; cire cuitadvantages. accruefrorntlie comnactness and low. impedanceconnectionsbetween elements. and electrodes.v Such. low impedance paths areynrovided between the screen. grid. elementsbetween thetwo screen grid.sections of. a double screen grid tube. and betweentlic. screen grid.structure and cathode. Oi equal` importance in ultra-high frequencyampliers is the very short length of neutralizer element (describedhereinafter). that is ncrmittcdwhen. mv structure is usedl of theseieatures combine to provide. excellent elecmeal, stability in.anultraehieh ireouencv duplex grid amnliiier- '.Ine. screengridstructure Provides. rrccisionA mounting. and aliennlentoi theelements which. is. unalected bv the. processing temperatures andlbynormal ooeratinaconditlons.

The anode-electrodes .26 and. 2.6! are-similar and aremountecl opposite.sides of. the. cathode ele..- ments 20, with collector surfacesn,Eieuresfi and @..very'closeto the screen. gridelectrodes. Theseelectrodesshown inFigures 1,l 5, 'l and ll.- are` made up of. twoblocks,104. and lllaof metal..` Tlccbloclss of Inetal are silver soldered toform, vacuurntight joints. The blocks |04 and IQE have slots or Channelsor grooves in the face of one or both thereof. toform 'fluidpassagewavsthrough which the cooling uid is forced. These passageways are carty ofthe device envelope and the joints thereof are` to. be. va.cuumtiglrlt,y One end of the anode. proper terminates in a hollowmetallic block. L05 (Eieures'l. 5.,A 7 and 11.)A into which a fluidconductor |01 is coupled- This. block sup.

plies cooling fluid to the slots in the anode blocks |04 and |06. Thisfluid conductor and its continuation has several functions. In additionto being a fluid conductor, this conductor with continuations acts as amember of a tuning line connecting the anodes in a resonant circuithaving low inductive reactance. The line |01 may be sealed into a glassinsert |08 forming part of the wall of the electron discharge device. Tofacilitate bonding between the glass and line |01 the line may be ofKovar at |01" where it passes through the glass |08. The glass |08 is inturn sealed into a thimblelike member |09 of Kovar which is sealed intothe header I' by welding or the like. The member |09 is recessed so thatcooling fluid may be fed therethrough by pipes |09. The pipes 01 asconstructed and sealed into the header I0 provide good strong supportsfor the anode electrodes. The members |01 also provide the electricalcircuits for the anodes. The other end of the anode proper terminates ina hollow metallic block The hollow block has an opening therein intowhich an outlet pipe member 3 is coupled. This pipe is insulated fromthe electron collector block |04|06 throughout most of its length. Theoutlet pipe ||3 passes through the block |05, into which it is sealedbyV a fluidtight joint, and extends within a metallic thermal insulatingpipe ||5 (Figure 5). The insulating pipe I |5 extends within the outerconductor 01 and extensions thereof. The channel between the pipes ||3and ||5 is closed at I1, i. e., about where this pipe enters the hollowblock |05 and is terminated. Thus if cooling fluid enters between thepipes ||5 and 3 there can be no flow therein since the path is closed atone end. The cooling uid may be supplied as indicated by the arrows tothe pipe 01 and taken from the pipe ||3. The thermal insulating pipe ||5traps a liquid layer which acts to insulate the cooling fluid within thepipe ||3 from that within the tube |01 and exterior to tube 5. Thisthermal insulation is obt-ained since the liquid trapped between pipes||3 and I5 has zero velocity with respect to the retaining pipe surfacesand there results a large temperature drop in the liquid-metalinterfaces. The fluid inlet pipe |01 is continued through the wall ofthe tube forming part of a transmission line or anode tuning circuit.Member |01 forms one member 0f a parallel line and member |01 forms theother member of this line.

My anode as cooled permits anl electron bombardment power input per unitarea of bombarded surface in excess of 800 Watts per square centimeterwith a reasonable water flow and pressures not in excess of '70 poundsper square inch. By insulating nearly all of the return tube |3 from theanode block heat exchange between input and output coolant in the anodeblock is eliminated. Thevdoubled walled pipe arrangement wherein thecoolant is trapped insulates the input coolant from the output coolant.The liquid cooled anode header glass |08 to metal seals permits use ofseparate anode header seals which are, per se, cooled. and are useful athigh power levels and at high frequencies.

The electron discharge device electrodes as described supplyconsiderable concentrated power in the form of electron beamsoriginating at the U-shaped cathodes. The beams pass in concentratedsheets toward the anodes and considerable heat is generated. A shield|20, Figures 9 and 10, is interposed between the central portion of theU-shaped cathode elements 20 and the Control grid and screen gridsupporting structures to prevent emission from the central portions ofthe cathode elements from reaching these supporting structures. Supportmembers |22 and |22' are soldered to the main support 35 above andbelow, respectively, the members 34 and 34". The member |22 (Figure 10)is reduced in size at |23 to form a shoulder that engages with themember 35 (Figure 9) to which it is soldered or other Wise fastened. Apin at |24 in the member |22 serves to locate the member properly duringassembly of the electron discharge device. The member |22 (Figure 9)also has drilled therein a locating pin hole |24' and is fastened to theother end of the main cathode support member 35. The members |22 and|22' extend beyond the U-shaped cathode elements and are drilled at |25and |25 as shown in Figures 9 and 10. The member |20 has end portions|20' and |20" bent at right angles to the V-shaped main portion andthese end portions are drilled to receive bolts which are threaded intothe holes |25 and |25' in supports |20 and |22 to fasten the shield |20rigidly between the cathode elements 20 and the control grid and Screengrid supports including fluid conductors CP, CP', etc.

Since an object of my invention is to increase the power output of theelectron discharge device, close electrode spacing is to be used. Thusthe control grid and cathode are close together and precautions must betaken to prevent movement of these electrodes toward or from each other.The cathode and its support is so rugged that the chance of it movingout of alignment in operation is very slight. The same is true of thecontrol grid support. However, the control grid support is not as rigidas the cathode support and pressure change in the fluid flowing in pipesCP, CP' might cause the grid structure :to sway. The control gridelectrode is therefore further stabilized with respect to later movementbut is permitted to move slightly in a direction normal to the surfaceof the base plate I0. This bracing of the grid electrode against lateralmovement is accomplished as follows. A mica member |30, Figures 9, 11and 14 is bolted at one end to the member |22. The bolts used to fastenthe heat shield member |20 may serve to fasten the mica element |30 tomember |22. The free end of the mica member |30 is split and one fingerthereof is bolted to a support member |35 and the remaining finger isbolted in like manner to the support member |35'. Spacers |31 and |31are placed between the mica member |30 and the members |35 and |35'. Theends of the control grid cooling pipes and supports CP and CP are capped(fluid flow reversed) and the members 35 and |35 are Welded, soldered orotherwise fastened to the ends of these pipes. This mica member as usedinsulates the control grids from the cathode support, yet prevents anylateral movement of the grids relative to each other or to the otherelectrodes of the device.

The electron discharge device of my invention includes built inneutralizing capacitors connected between the control grid of one of thedevice sections and the anode of the other section, and between thecontrol grid of the said other section and the anode of said onesection. These neutralizing capacitors are shown best in Figures 9 and11. The control grid supporting pipes CP and CP' are terminated in capsat the ends remote from the main header |0 wherein the uid is turnedaround to ow out. Members |35 and 13r |35f'are solderedwelded Vorotherwise fastened tothe end 4caps of grid cooling pipe supports CP and'CP'. The neutralizing capacitors |60 and |69 are fastened to thesesupports |35 and |35. The members |35 and |35' extend outwardly inadirection parallel to a'plane passed between the cathode emittingareas. The members |35 and |35' are drilled near the outer endsand themembers Hill and |60 are bolted thereto. The membersl and |60 extend in-opposite directions from said aforesaid plane 'and then turn back andup at |G| and IBI' to face a considerable area of the respective anodes26 and .26'. These elements .form the capacitors NC and NC' of' Figure 1and are .dimensioned and. adjusted toA compensate and neutralize thecapacity within the tube directly between the control grid and anodes.It will be noted that the beam focussing electrodes-have not beenincluded in the circuit of Figure 1. omission thereof simplifies thecircuitsand permits better Showing of the remaining elements and builtin capacitors.A

` The'electron discharge device of my invention is .further adapted. forstable `operation in high frequency circuits by provision of a novelshield arrangement between the control grids and con-A nectors CP, ACPandthe anode and screen grids and r.t'heirvconnectors.. This shield isshown in Figures .4 and Gand comprises sidemembers |70 and |18 .boltedto the respective screen grid frame members 85 and 85' (Figure 10). Theside members extend in a direction parallel to a plane passed betweenthe cathodes to a point beyond the control grid pipes CP. and CP'. Anend plate |12 is fastened betweenthe endsof side plates 85 and 85 tocompletely block coupling between the control grid and its leads CP andCP and the anode and screen grid and their connectors. The end plate |72is trapezoidal'to form a trapezoidal frame open at one end.

To facilitate assembly and adjustment of the tubecharacteristics, theheader .plates l0 and l0 are made adjustable. their supports, thecontrol grids, their supports, the screen grids, their supports and theuid circuits .and electrical circuits may be assembled and mounted onheader plate |ll. The anode electrodes and electrical andfluid circuitstherefor may be assembled on the header I0. The tube envelope is thenassembled and the holes -in the rings 48 and dd are machined oversize sothat the header plates may be moved slightly as de.

sired toproperly relate and space the electrode structures fastened tothe two plates.' The bolts 65 and 36' are then tightened tocompress thecopper gaskets im and 50' to make a vacuum tight joint between theheaders lil and l0' and the side walls'formed by cylinder I2. The endsof cylinder i2, are rounded off and the copper gaskets 50 and 5B' areeach compressed between a fiat surface (on plates, 4|) and 40') and therounded sur-` faces at ,the ends of. cylinder |2. The spacer rings '|39and 49 prevent warping and deformation of the clamping rings 48 and 48when pressure is applied. This noveladjustable header method of tubeconstruction and assembly provides a practical method for theconstruction of evacuated devices requiring closely spaced elements. Thedouble screen grid tube is such a device and the cathodes, grids, andscreen grids may be conveniently aligned and spaced with the headerplate it removed from the envelope. The anode structure on the headerplate Ill may be handled in like manner. The adjustments provided.permit accurate balance in spacing and capacitance Then the cathodesections,`

14 between the anodes and screen grid structures. An electron dischargedevice assembled in ac-l cordance with my invention is convenientlydisassembled for repairs. v Y l* In an embodiment which operated wellata frequency of ina/sec. lthe double cathode` structure has a length ofabout 6.00", the active parts lof the U-shaped cathodes are about 1"oneach leg. There were 13 U-shaped elements in each of the Vthreegroups. The dimensions of each control grid, screen grid and anode arecommensurate with the dimensions of the cathode structure. Each controlgrid is spaced about .050" yfrom its cathode section. Each screen grid`is spaced about .115 from its control grid and each anode is spacedabout .167 from its screen grid l' j The planar electron emittingsurfaces of thev cathode ystrips function to provide substantially lWhere@ is the transit angle, J is the electron beam current density and(S)V is the effective spacing between the cathode and grid, this beingthe r'egion of interest for transit angle considerations. These fieldsand configurations permit increased current densities and decreasedtransit angles making possible high frequency,l high power outputs.` Inthe embodiment described, 'the tube operated Well at 100 megacycles andan output of 50 kw.

I claim:

1.1A cathode'for providing a plurality of .directed` concentrated`sheet-like beams comprising a plurality of elongated. emitting elementsseparated by spaces and an elongated non-emitting conducting element ineach space, said non-emitting-elements being detached from and extendingbeyondthe emitting elements in the direction of said beams and a commonconductive support connectingsaid emitting and' non-emittingelementsonly adjacent ends thereof. i

2; A cathode for providing a plurality ofoppositely directed elongatedelectron beams-along spaced paths comprising a beam focussing assemblyhaving on oppositesides thereof parallel non-emitting conductingelements in a plane separated by 'spaces for receiving elongatedelectron emitting elements and an elongated electron emitting elementdisposed in each of said spaces said non-emitting elements beingdetached from said emitting elements, and conductive support meansconnecting said emitting and non-emitting elements only adjacent endsthereof.4

3. An electron emitting structure including a main support in the formof a metallic strap-'like member, a secondarysupport in the form of ametallic strap-like member insulated-from said rst member toformi'therewith a capacitor and elongated cathode elements fastened atone end to theqmaingsupport andgat theother end ,to thev Secondarysupportt19A-cathode structure including a main sup. port in the form ofa rectangular `metal bar, a secondary supportin the form of arectangular metal bar adjacent said` main support and insulatedtherefrom to form therewith a capacitor, elongated cathode elementsfastened at one end the main support and at the other end to the isecondary support, and fluid conducting channels cooperating' with saidsupports for extracting heat therefrom.

5. A cathode structure comprising a main support in the form of arectangular metal bar, a plurality of secondarysupports in the form ofsimilar bars of less length adjacent said main bar to'form therewithcapacitors, elongated cathode elements each fastened at one end to saidmain support and at the other end to a secondary support, there beinggroups of. cathodes for each secondary support, and means for supplyingmultiphase currents to said cathode elements comprising a commonconnection to said main support andA separate connections to each vofsaid secondary supports.

6, A cathode structure comprising a main support in the form cf metallicstrap, a secondary support in the form of a metallic strap insulatedfrom said first strap to form therewith a capacitor, U-shaped cathodeelements having one leg fastened to the main support and the other legfastened to the other support, and beam focussing electrodes fastened tothe main support and to the secondary support, said focussing electrodesbeing located between the legs of adjacent U-shaped cathode elements;

'7. An electron beam emitting and beam focussing structure including amain support in the form of an elongated rectangular metal bar, asecondary support in the form of a similar elon-V gated metal bar boltedto said first bar and insulated therefrom, a plurality of spaced cathodeelements each having one leg fastened to said secondary support and theother leg fastened to said main support, focussing elements fastened toboth supports in the spaces between the leg of said cathode members, andfluid conductors in said supports for extracting heat therefrom.

8. A cathode assembly comprising a pair of elongated oppositely disposedconductors, a plurality of U-shaped emitting elements in spacedregistering relationship and having their ends secured to saidconductors and elongated conductors positioned in the spaces betweensaid U'- shaped elements and having one end connected to saidconductors.

9. An electron discharge device having within an evacuated containercathode elements, electron beam focussing elements separating thecathode elements, a common support for said cathode and beam focussingelements and fluid conductors for said support for extracting heatherefrom.

10. An electron discharge device having within an evacuated containercathode elements, electron beam focussing elements separating thecathode elements, a common support for said cathode and beam focussingelements', an anode electrode, a support therefore, a grid electrodeinterposed between said anode electrode and cathode elements, a supportfor said grid electrode and fluid conductors cooperating with each ofsaid supports for extracting heat therefrom.

11. A double cathode structure comprising two support members ofconsiderable surface area facing l eachother thrquh. any insulatingmedium toformfa Ylarge capacitor, 'electron emitting ele- 412,., A4double jcfathode structurev comprising two support membersl vofconsiderable area facing each other through an insulating medium toforma ,large capacitor providing low alternating currentiinpedancesbetween these support members, `a plurality of `spacedelectron emitting elementslsupported by Ieach ofhsaid support mein;-bers and Ia4 beam focussinglelectrode inv each of heSDaGCS, between,sasiiemitting elements-,

13-efd9ub1e cathode Structure comprising. two suimorhmembers of,,considerable surface area facineeahther t0. form alarga capacitor, anda plurality ofI lll-shaped` members witheone leg df eah; l.1,'-Shapesi,membr fastened t0. one of. Said Subpart members: and. the other. lespreach U- shap'e'd in e'mb'er fastened tothe other of saidA supportmembers. 4 e Y Y 14. A doubley cathode structure comprisingtwo support,memberserf Considerable, area faccine @2191.1r other through, an.insulating medium to formaler@ Capacite. a plurality ,of .l1-Shapedelectron emitting electrodes, said U-shaped meibrs having. 'oneleafstenedto one 0f said supportsv and the lothenleg fastened to theother of said supports andbeing in spaced relation, and an electronfoc'u ing electrode in each of the spaces zbetween said Li-shapedmembers.

145 An electron discharge device comprising two support members of Yconsiderabler surface rea ffwiie each other through Yan insulatingmedium to form a largeicapacitor, spacedelectron emitting elementssupportedlby each of said support members toV emit two electron beams.beam guiding elements, in, the spaces between said emittingelementasupported by said supports, a control grid element adjacent eachcathode structure, two other supports of considerable surface areafacingA said first supports through insulating materialto form therewithlarge/,capacitors, and screen grid elements mounted on said two othersupports.

16. A push-pull electron discharge device of the screen grid type havingelectrodes including two cathode sections, a support for each therefor,two screen grids, a support for each therefor, and means for maintainingsaid cathode sections and screen grids at substantially the samealternating current potential forming capacitance between said supports.

17. An electron discharge device electrode structure comprising ametallic support, a plurality of elongated electrode elements fastenedat one end to said support, fluid conductors cooperating with saidSupport to extract heat therefrom, said elongated electrode elementsbeing short enough so that the entire length of the elements is cooledby heat conduction along the element to the 2&0) A grid structureVcomprising two rigidly spaced side members, and a plurality ofelongated metallic elements extending from the side members toward eachother-to nearly meet.

21. A grid structure comprising two rigidly spaced parallel metallicside members, and a plurality of rod-like elements extending in spacedrelation from each side member toward the other side member to nearlymeet.

22. A double grid member comprising a rst support comprising two rigidlyspaced side members, a second support comprising two rigidly spaced sidemembers, frame members for rigidly holding said supports yin parallelplanes and a plurality of elongated members extending from each sidemember of each support toward the other side member of each support tonearly meet in the space therebetween.

23. In an electron discharge device, a grid structure comprising ametallic picture framelike member, a plurality of grid elements fastenedto opposite inner peripheries of ysaid frame-like members and extendingtoward each other to nearly meet, an envelope enclosing said gridstructure and a support in said envelope for said grid structure. Y

24. In an electron discharge device, a grid structure comprisingametallic frame member, a plurality of grid elements fastened toopposite peripheries of said frame and extending toward each other tonearly meet, a cathode structure, an envelope for said grid and cathodestructures, a support in said envelope for the cathode structure and acapacitor built into said support, one plate of said capacitor servingas a support for said grid structure.

25. In an electron discharge device, a double grid structure comprisingtwo metallic frame members in parallel planes, metallic side piecesfastening saidl frames in rigid relation in said parallel planes, aplurality of rod-like elements extending from'opposite inner peripheriesof each of the frames toward each other to nearly meet, an envelopeenclosing said structure and a support in said envelope for `said*double grid structure.

26. A cooled anode, structure comprising an active surface and a fluidpath adjacent thereto comprising an inlet pipe coupled to one end ofsaid path, an outlet pipe coupled to the other end of said pathandgpassing within said inlet pipe, and a Iluid trap in the form of asecond pipe surrounding said outletpipe within said inlet pipe. s A

27. An anode electrode for an electron discharge device comprising amember having a plurality of parallel passageways extendingtherethrough, a tubular member connected to and supporting said anode,one end of said parallel passageways communicating with said tubularmemf ber and another tubular member within said `first tubular memberand communicating with the other end of said passageways.

28. An anode electrode for an electron discharge device comprising ahollow member having passageways extending therethrough, a tubularmember connected toand supporting said anode, one end of saidpassageways communicating with said tubular member, `and, tubular meanswithin Y thereof which are in register to form fluid channels, a hollowmember at one end ofsaid bars to completea cooling uid path to one endof saidchannels,`a hollow member at the other end of said bars tocomplete a ud path to the other ends of said channels, a fluid conductorcoupled into said first hollow member and a fluid conductor'coupled intosaid second hollow member and passing through said first hollow memberand within said first-named uid conductor.

30. An anode electrode comprising two rectangularr elongatedmetallic'bars having a plurality of longitudinal channels in one face ofat least 'one thereof, said bars being joined together atsaid facestoform fluid channels which are vacuum-tight, a hollow member at one endof said bars to complete a cooling huid path to said channels, a firstiiuid conductor coupled into said hollow member to complete a iluid pathbetween the same and an external fluid source, a second hollow capmember at the other end of said bars to complete a fluid path to theother end of said channels, 'a second fluid conductor coupled into saidlast-named hollow member and passing through said first-named hollowmember and within said first fluidvconductor to form a second nuid pathto 'said external source and a dead end conductor enclosing said secondconductor within' said first-.named conductor to provide thermalinsulation for said second named con- 35': for said opening, at leastone electrode mounted ,L'Otand'means for relatively adjusting therelative positions of said electrodes to establish symmetry of thedevice including means for adjusting the position of said closure memberrelative to the opening insaid hollow member.

32. An electron discharge device comprising an envelope including ahollow member havingan opening therein, a closure member for saidopening, an anode' electrodemountedin said envelope, electron dischargedevice electrodes including a screen grid mounted on said closure memberand extending into the hollow member in electronically operative,relation to said anode electrode, and means fo1 ,relatively adjustingthe,

relative position of `said anode and screen grid to adjust the couplingtherebetween including an adjustable joint between said closure memberlvelope to face eachother in lelectronically op-` erative relation, andmeans for adjusting the positions of at leastr ,one4 closure memberrelative to the opening closed thereby to adjust thek relation of saidelectrodes Vsaidmeans including an adjustable joint.

i 34. VInman electron discharge device, a hollow. envelope member havingopenings in opposed walls thereof, a yclosure member for each `open-ling, at least ,onenelectrode' structure on each closure member and.leadspthereto extending, through the closure member, said electrodestruc,-YV tures eachy including' an electrode extending 19 within thetube in electronically coupled relation to each other, and apparatus forfastening said closure members over said openings and adjusting theposition thereof relative to the openings to change the electroniccoupling between said electrodes.

35. An electron discharge device having an envelope including a headermember, a cathode assembly supported from said header member, a screenelectrode insulatingly supported from said cathode assembly andsurrounding said cathode assembly, said header member having a pluralityof apertures extending therethrough, and leads extending from saidcathode assembly and through said header, and a lead extending from saidscreen electrode and through an aperture, and a control electrodepositioned between said cathode assembly and screen electrode and havinga lead supporting said control electrode from said header member andextending through another of said apertures, and a closure member forsaid header member for providing an envelope, an anode adjacent saidscreen electrode, and a lead extending through said closure member andsupporting said anode.

36. An electron discharge device having an envelope including a headermember, a cathode assembly and a screen electrode insulated from eachother, said header member having a plurality of apertures therethrough,and a plurality of leads extending from said cathode, one of said leadsextending through one of said apertures, and a lead extending from saidscreen electrode and through another of said apertures, and a controlelectrode positioned between said cathode assembly and screen electrodeand having a lead supporting said control electrode from said headermember and extending through another of said apertures, and a closuremember for said header member providing an envelope, an anode, and alead extending through said closure member and supporting said anodeadjacent said screen electrode, said leads compiising tubular membersand providing a transmission means for a coolant to and from saidcathode assembly, electrodes and said anode.

37. In an electron discharge de'vice, an envelope enclosing electrodesincluding a control grid, a support for said control grid including acoolant conductor sealed into said envelope, said conductor also servingas an electrical connection to said control grid, other electrodes insaid envelope, electrical connections from said other electrodes passingthrough the Wall of said envelope and a metallic shield supported by oneof said other electrodes and extending between said grid support andsaid other electrodes and their electrical connections.

38. In a push-pull electron discharge device, an envelope having anopening therein to be closed by a header member, two anodes supported insaid envelope, other electrodes including two control grids and twoscreen grids carried by said header and extending within said envelopein electronically coupled relation to said anodes, said header beingadjustable relative to said opening to establish mechanical andelectrical symmetry between said anodes and screen grids, andneutralizing capacitors within said envelope cross coupling said anodesand control grids.

39. An electron discharge device comprising an envelope enclosingelectrodes including two anodes in the form of metal blocks with luidchannels therein, and supports for said anodes comprising parallelcoaxial iluid conductors for each 20 anode extending through theenvelope of said device, said coaxial fluid conductors serving to supplycooling fluid to and take cooling fluid from the respective anodeblocks, said parallel coaxial conductors also serving as a part at leastof a resonant circuit for said anodes.

40. In an electron discharge device, an envelope including a metal wall,a cathode structure on a cathode support carried by said metal Wall andextending therefrom within said envelope, a grid structure on a gridsupport carried by said wall and extending therefrom to face saidcathode in electronically operative relation, and a brace fastenedbetween the ends of said supports remote from said wall to preventrelative movement of the grid and cathode structures.

41. In an electron discharge device, an envelope including a metal wall,a cathode structure on a cathode support carried by said metal wall andextending therefrom within said envelope, a grid structure on a gridsupport carried by said Wall and extending therefrom to face saidcathode in electronically operative relation, said cathode support andsaid grid support including metallic uid conductors extending from thecontrol grid through the envelope, said fluid conductors serving toextract heat from the cathode structure and grid structure and to formelectrical Connections thereto, and a brace fastened between the ends ofsaid supports remote from said wall to prevent relative movement of thegrid and cathode structures.

42. An electron discharge device having an envelope including aconducting header member, a cathode assembly and a screen grid assemblyinsulated from said cathode assembly, said cathode and screen gridassemblies being supported from said header member, said header memberhaving a plurality of apertures therethrough, and a plurality of leadsextending from said cathode assembly, one of said leads extendingthrough one of said apertures and insulated from said header member, anda lead extending from said screen grid assembly and through another ofsaid apertures and insulatingly sealed therein, and a control electrodepositioned between said cathode assembly and screen grid assembly andhaving a lead insulatingly supporting said control electrode solely fromsaid header member and extending through another of said apertures andsealed therein, and a closure member for said header member providing anenvelope, an anode adjacent said screen grid assembly and a lead forinsulatingly supporting said anode from said closure member.

43. An electron discharge device having an en-` velope including aconducting header member, a cathode assembly supported from said headermember, a screen electrode insulatingly supported from said cathodeassembly and surrounding saidv cathode assembly, said header memberhaving a plurality of apertures extending therethrough, andleadsextending from said cathode assembly and through said header, and a leadextending from said screen electrode and through an aperture andinsulatingly sealed therein, andl a control electrode positioned betweensaid cathode assembly and screen electrode and having a leadinsulatingly supporting said control electrode from said header memberand extending through another of said apertures and sealed therein, anda closure member for said header member for providing an envelope, andan anode adjacent said screen electrode, andy a lead ex- 21 tendingthrough and insulatingly sealed in said closure member and supportingsaid anode.

44. An electron discharge device having an envelope including aconducting header member, a cathode assembly and a screen electrodeinsulated from said cathode assembly and said cathode assembly and saidscreen electrode being supported from said header member, said headermember having a plurality of apertures therethrough, and a plurality ofleads extending from said cathode, one of said leads extending throughone of said apertures and insulated from said header member, and a leadextending from said screen electrode and through another of saidapertures and insulatingly sealed therein, and a control electrodepositioned between said cathode assembly and screen electrode and havinga lead insulatingly supporting said control electrode from said headermember and extending through another of said apertures and sealedtherein, and a closure member for said header member providing anenvelope, an anode, and a lead extending through said closure member andsupporting said anode adjacent said screen electrode, said leadscomprising tubular members 25 and providing a transmission means for acoolant to and from said cathode assembly, electrodes and said anode'.

PHILIP T. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

